fix(@ngtools/webpack): avoid non-actionable template type-checker syntax diagnostics
fix(@ngtools/webpack): avoid non-actionable template type-checker syntax diagnostics

The AOT compiler's internal template type-checking files are not intended to be directly analyzed for diagnostics by the emitting program and are instead analyzed during the template type-checking phase. Previously, only semantic diagnostics were ignored. Now both syntactic and semantic diagnostics are ignored. This change prevents non-actionable diagnostics from being shown during a build.

Addresses: https://github.com/angular/angular/issues/42667

clydin/angular-cli,Brocco/angular-cli,angular/angular-cli,catull/angular-cli,Brocco/angular-cli,clydin/angular-cli,angular/angular-cli,geofffilippi/angular-cli,catull/angular-cli,angular/angular-cli,catull/angular-cli,Brocco/angular-cli,clydin/angular-cli,geofffilippi/angular-cli,geofffilippi/angular-cli,geofffilippi/angular-cli,Brocco/angular-cli,angular/angular-cli,Brocco/angular-cli,clydin/angular-cli,catull/angular-cli